Clipper machine



March 12, 1957' G. HAUMANN CLIPPER MACHINE Filed Oct. 26, 1953 4 Sheets-Sheet 1 JNVENTOR. George Haumann BY March 12, 1957 G. HAUMANN ,7 ,784

- CLIPPER MACHINE Filed Oct. 26, 1953 4 Sheets-Sheet 2 I :98 Haumann Y JLIL I m ml -III' I I m H Y J r i H 3; g m g v March 12, 1957 G. HAUMANN 2,784,784

CLIPPER MACHINE INVENTOR. eorge Haumann BY March 12, 1957 G. HAUMANN CLlPPER MACHINE 4 Sheet sSheet 4 Filed Oct. 26-, 1953 1T R r a ma mH W GY B R Lm. FM

CLIPPER MACHINE George Haumann, Portland, Greg, assignor to Moore Dry Kiln Company, North Portland, Greg, :1 corporation of Oregon Application October 26, 1953, Serial No. 388,311

Claims. (Cl. 164--68) This invention relates in general to machines for cutting or severing sheet material into strips of desired length, and, more specifically, relates to the cutting or socallec clipping of desired lengths from a continuous sheet of material, particularly wood veneer as the wood veneer sheet is received from the veneer lathe or log peeler.

As is well known, there are generally portions of the veneer sheet which are notsuitable for ordinary use, due to knots or other defects, and the operator in charge of the cutting or clipping of the veneer sheet must, in addition to cutting the desired lengths from the sheet, also cut out unusable parts in order that the desired lengths as cut will meet requirements for use. Thus, the operator must watch the sheet constantly so that such unusable parts will be cut out and so that this will be done with as little waste as possible while the usable portions are cut into the desired lengths.

A general object of the present invention is to provide an improved clipper machine in which the work on the part of the openator will be facilitated and simplified.

A related specific object is to provide an improved veneer clipper in which the operator willhave full and unobstructed view of the veneer as it is received and up to the point where the cutting or clipping occurs.

A further related object is. to provide an improved veneer clipper wherein the control of the operation is carried out by the operator merely by the pushing down of control buttons, thusreducin'g to a minimum the amount of actual physical labor and strain imposed on the operator.

A further object of the invention. is to provide an improved. clipper machine through which the veneer or other material being out can be moved and cut at any desired rate of speed, depending upon the nature of the material and the skill of the operator in directing. the cutting andin selecting and eliminating unusable parts of the material. Another object of the invention, is to. provide an im proved clipper machine which will be lighter in Weight and less expensive to manufacture than: some of the veneer clippers now in current use.

An additional object of the invention is to provide an States Patent 0 improved clipper machine requiring a minimum amount of expense and care in maintenance.

The manner in which these objects and other incidental advantages are attained, and the construction, arrangement, and method of operation of the machine and of the individual parts, will be readily understood from the following brief description with reference to the accompanying drawings.

in the drawings:

Fig. 1 is a fragmentary and more or less diagrammatic side elevation of the entire device;

Fig. 2 is a fragmentary, longitudinal vertical sectional view, drawn to a larger scale, of aportion of the operating control chain, together with aportion, of the driving sprocket over which the control chain passes;

2,784,784 Patented Mar. 12, .1957

Fig. 3 is an enlarged sectional elevation of one of the control button carrying members of the control chain;

Fig. 4 is a fragmentary longitudinal vertical section showing the clipper knife assembly and the supporting sprockets and knife-operating roll, and also illustrating the position of the knife assembly and knife blade with respect to the anvil roll, part of the. section being taken on line 4-4 of Fig. 5;

Fig. 5 is a fragmentary transverse vertical section through the knife-operating roll assembly showing one end of the knife-operating roll and the mechanism for moving the knives into operative position;

Fig. 6 is a fragmentary plan view of the knife assembly taken on line 6-6 of Fig. '4;

Fig. 7 is a fragmentary section taken on line 7'-7 of Fig. 5;

Fig. 8 is a similar fragmentary section on line S--8 of Fig. 5;

Fig. 9 is an elevation of one of the special links of the knife assembly chains, withportion broken away and part shown in section, illustrating the mounting cylinder for one end of :a knife-carrying member, theview being taken on line 99 of Fig. 6, but drawn to a larger scale; and

Fig. 10 is a schematic wiring diagram illustrating the operation of the control circuits for the device.

Referring first toFig. l, thedevice includes a rigid frame structure having a receiving and delivering portion, indi cated in general by the reference character 10, a discharging portion, indicated in general by the reference character 11, and a central housing within which most of the operat ing mechanism is supported. The central housing has a pair of side members or standards 12, one of which is shown in Fig. l, and these standards 12. provide journal supports for the shafts onwhich various sprockets and rolls or drums, hereinafter mentioned, are mounted. A plurality of endless conveyorbelts 13" are mounted on the receiving and delivering portion of the machine. These conveyor belts 13 are spaced apart laterally and pass over sheaves 1 4 at one end, over intermediate supporting rollers, and over driven sheaves-151M the other end. Similarly a plurality of conveyor belts 16 are mounted on the over a rotating anvil roll 19, after leaving the delivery conveyon belts 13, andthence passes on to the discharging conveyor belts16.

While passing over the anvilroll'19,.tlie material moves below a moving clipper knife assembly, which clipper knife assembly passes around a knife operating roll 20. The axis of. the roll 20 and the axis of the anvil roll 19 extend in the-same vertical plane.

An endless control chain 21, to-be presently described;

located on. the near' side of the machine, asviewed in Fig. 1, passes over an idler sprocket 22 and over a driven sprocket 31 (Fig.2) securechto and'rotatedwitlr the anvil roll 19 (Fig.1).

The anvil roll. 19,- the knife-operating roll 20, the

sprocket for the controli chain 21, and. the drivensheaves 15 and 18 for the sets of. conveyor belts 13 and lfi are all driven at the same peripheral speed by a motorP, which is connected upin the, manner. indicated by the broken.

lines in Fig. 1. Thus, the speed atwhich the entire machine operates can be varied by varying the speed. of the motorP. i

The control chain-or knife-setting chain 21. (seeFigs. 2 and 3) consists of a series-of uniformly-spacedlblocks or control button carrier membrsZ'S which are connected by pairs of links 24. A cylindrical channel extends through each of the members 23, the axis of the channel being normal to the direction of travel of the chain, and the shaft -for a control button 26 is mounted in each cylindrical channel for limited movement in an axial direction therein. A friction ring 27 (Fig. 3) in each cylindrical channel prevents any inadvertent movement of the shaft 25 in the cylindrical channel. A contact knob 28 is secured on the shaft on the opposite end from the control button 26 and is adapted to engage an e m'ent 29 (Fig. 2) of a spring-biased switch assembly 31? so as to cause momentary closing of the switch in the switch assembly when a control button 26 is pressed down manually into lowered position to cause the contact knob 28 to engage the element 29. The control chain 21 passes around the driven sprocket wheel 31 and the sprockets 32 of this sprocket wheel are specially shaped and arranged so that they will engage the openings between the pairs of links 24 while the contact knobs 28 will be engaged by the pocket portions 33 between the sprockets, as shown in Fig. 2. As a result of the engagcment of the chain 21 with the sprocket wheel 31, any control buttons which have been pressed down in the chain, for operating the switch assembly 30, will be returned to normal position when the chain encounters the sprocket wheel 31.

Referring now to Figs. 4, 5, 6 and 9, the clipper knife assembly includes a series of transversely-extending T- shaped knife carriers 34 which are supported at their ends on conveyor chains. These conveyor chains are formed with special chain links 35 (see Fig. 9) which have hollow slotted cylindrical castings 36 into which the respective ends of the knife carriers extend. A knife blade 37 (Figs. 4, 5 and 6) is bolted on each knife carrier 34. A coil spring 38 (Fig. 9) in each cylindrical casting 36 acts to hold the knife carriers 34, and therewith the knife blades 37, normally in inoperative position in which position the knife blades will not c0ntact the material M passing over the anvil roll 19 and under the knife blades (see Fig. 4).

The conveyor chains of the knife assembly, having the special links 35 with the cylindrical castings 36, are engaged by sprockets secured to each end of the knifeoperating roll 20, one such sprocket being shown at 39 in Fig. 5. These conveyor chains also pass over idler sprockets, one of which is shown at 40 in Fig. 4.

The knife-operating roll 20 carries a plurality of slide bars 41 (Figs. 4 and 5) which coincide with the knife carriers 34 respectively as the knife assembly passes around the roll 20. Each of the knife carriers 34 has a plurality of spaced, inwardly-projecting lugs 42 and each of the slide bars 41 on the knife-operating roll 20 is formed with corresponding recesses 43 for receiving these lugs when the slide bars are in normal inoperative position. Each of the slide bars 41 has secured thereto a rod 44 which extends from one end of the slide bar (Fig. 5) in alinement with the slide bar and thus parallel to the axis of the roll 20. Each rod 44 extends through an opening in the adjacent sprocket 39 for the knife assembly chain and is movable, by means later described, to produce slight sliding movement of the connected slide bar 41.

Thus, as apparent from Fig. 5, when a slide bar 41 is moved from the normal inoperative position, shown by the upper slide bar 41 in Fig. 5, to the position shown by the lower slide bar 41 in Fig. 5, the lugs 42 of the knife carrier 34 will be engaged by the slide bar and the engaged knife carrier will be pushed radially outwardly, with respect to the roll 20, against the force of the springs in the cylindrical castings 36, and will move the attached knife blade 37 into cutting position. In Fig. 4 the lowest knife blade 37 is shown as having been moved outwardly (and consequently downwardly) into cutting position, and in such position cuts through the material M passing over the anvil roll 19 as the knife blade reaches the anvil roll.

An air piston 45 (Fig. 5) is mounted on the outer end of each slide bar rod 44 and is positioned within an air cylinder 45. A spring 47, carried on each rod 44, is held under compression between the piston 45 and a shoulder in the aperture in the sprocket 39 through which the rod 44 passes. Thus each spring 47 exerts a force to move its corresponding piston 45, rod 44, and slide bar 41, to the left as viewed in Fig. 5, and thereby maintains the slide bar 41 in the normal position illustrated by the upper slide bar in Fig. 5, until compressed air is allowed to enter the cylinder 46 and force the piston 45 to the right against the force of the spring 47 as illustrated by the lower piston and slide bar in Fig. 5.

Compressed air from a suitable source (not shown) is delivered to the knife-operating roll assembly through a pipe 48 (Fig. 5) and thence through a rotary joint 49 to a pipe 50 which extends a short distance axially within the shaft of the knife-operating roll 20. Branch pipes 51 (see also Fig. 8) lead from the central pipe 50 and are connected with pipes 52 respectively, through the intermediary of solenoid-operated valve assemblies indicated in general by the reference character 53. The air pipes 52, in turn, connect with the air cylinders 46, as shown in Fig. 5. Thus, the knife-operating roll assembly carries a plurality of slide bars 41, an air cylinder and piston for operating each slide bar and a connection with a source of compressed air for each cylinder controlled by a. solenoid-operated valve.

A disc 54 (Figs. 5 and 7) is keyed on the shaft of the knife-operating roll 20. A plurality of relay switches, mounted in suitable housings and indicated in general by the reference character R, and corresponding in numher to the solenoid-operated valves and air cylinders of the knife-operating roll are carried on the periphery of the disc 54. Connecting wires from each relay switch lead to the solenoid for the corresponding solenoid-controlled valve 53 through a connecting tube 55. A panel 56 containing 3 contact brushes 55a, 56b and. 56c, is provided for each relay R and is positioned on the disc 54 substantially in radial alinement with the relay, as indicated in Fig. 7. Each of the 3 brushes of the panel is connected with the relay in the manner explained later.

A stationary ring 57 (Figs. 5 and 10), mounted on a bracket 58 which is secured to a standard supporting the shaft of the knife-operating roll 20, carries a pair of arcuate contact strips 57a and 57b and also a short contact strip 570, which are positioned as shown in Fig. 10, and are so arranged as to be contacted by the brushes 56a, 56b and 56c respectively of each relay R during each rotation of the knife-operating roll assembly. The two main contact strips 57a and 57b are electrically connected by the wires 59 and 60 (Fig. 10) to electric supply lines and 71 respectively. The short contact strip 570 is connected with supply line 71 through the intermediary of the spring contact switch 30 previous ly mentioned.

With reference to the diagram in Fig. 10, the electric control connection operates as follows:

When the brushes 56a, 56b and 560 of one of the relays R contact the strips 57a, 57b and 57c, respectively, as the knife-operating roll assembly rotates, assuming that the switch 30 is closed, the momentary contact of the brush 56c with the short contact strip 570 will energize a solenoid 61 close the contact 62, and close the relay circuit to the solenoid-operated valve 53. This will cause the valve 53 to open and the opening of the valve 53 will result in compressed air passing into the air cylinder 46 (see also Fig. 5), resulting in the movement of the corresponding slide bar 41 on the knife-operating roll 2?; and the moving of the corresponding knife blade out into cutting or clipping position.

As apparent from Fig. 10, once the contact is closed through the relayR to the solenoid-operated valve 53,

the connection with the contact strips 57a and 57b will be maintained even though the brush 56c passes beyond the contact strip 57c, and the connection will continue until it isfinally terminated by'the-tpassing ofthe brushes 56a and 56b beyond the end of lthestrips 57a and 57b. In other 'WOfdS, thecylinder 46 will continue to be connected with the source of compressed air, 1 and .the corre sponding knife will be held in operatingrposition, until the brushes of the correspondingrelayR have passed beyond the contact strips 57:: and 57b, at which time the knife will have completed the desiredcut'ting or clipping of the material.

The .fact that :thecontact strip 570 is so short ,prevents more than one relay R from being energized-at the instant closing of the control switch 30, and :at the same time enables successive relays R to be energized as desired by successive closings of the switchBt), the closing of the switch being controlled by the control buttons 26 in the knife-setting chain 21, as previously described.

The spacing of the control buttons 26 in the knife setting chain 21 corresponds exactly to the spacing of the clipper knives 37 in the knife assembly and the spacing of the slide bars 41 in the knife-operating roll 20. This spacing may be arranged at any desired equal intervals, such as the two inch intervals which recently have become more or less standard in veneer clipping machines. However, in the carrying out of my invention, I prefer to space the knives, and correspondingly the control buttons in the control chain 21, at intervals slightly in excess of the standard two inches, for example at intervals of two and one-eighth inches, with the excess one-eighth inch corresponding very closely to the amount of shrinkage which will occur in the veneer upon the drying of the same when the veneer is made from the type of wood at present extensively used in the plywood industry in the Northwest.

As is well known, the cutting or clipping of wood veneer takes place before the veneer has been dried, and with the preferred arrangement which I employ the veneer sheets will be of the uniform exact size desired after the cut sheets have dried.

The switch 30 and the short contact strip 570 are so located that the distance traveled by the veneer or other material from the point at which the switch 30 is engaged by a selected control button up to the point at which the veneer reaches the crest of the anvil roll 19 is equal to the distance traveled in the same period by a cutting knife from the moment the corresponding brush 560 contacts the strip 57c until this knife arrives at the top of the anvil roll. Since the control chain 21 moves along at the same rate of speed as the veneer or other material to be cut and is located close to and parallel to the edge of the material as it passes in front of the operator, while the knife assembly travels also at the same speed, the open ator knows that the cutting or clipping of the material will occur in exact registration with the control button which he selects. Consequently, all that is required of the operator is to select and push down a particular control button. The operator at all times has full view of the on-coming material or veneer, and, by cutting out entirely unusable portions of the material, can get the most out of the material as it is delivered to the machine with a minimum amount of effort and strain on the part of the operator.

The anvil roll 19 (Figs. 1 and 4) in my improved machine preferably has resilient material vulcanized or otherwise secured on its periphery. While the peripheral speed of the anvil roll is the same as that of the knife-operating roll 29, and thus the same as the speed at which the knife assembly travels, I purposely make the anvil roll in my machine with a slightly greater diameter than the upper knife-operating roll 20. The particular advantage in this is that the knives can perform a great many cuts without striking the anvil roll a second time in exactly the same spot. This feature considerably increases the life of the resilient layer with which the anvil roll is surfaced.

As will be apparent from Fig. 4, the cutting edges or bottom edges of the knives 3'7 momentarily rnove with increased speed after leaving the anvil roll 19 due to the fact that the knife assembly curves aroundthe roll 20 after leaving the anvil roll and the knife edges are spaced considerable distance radially from the roll 20. The temporary increase of speed by the outer or bottom edge of the knife blade aidsin pushing the cut-off piece of material slightly ahead after its severance on the top of the anvil roll.

Since the slide bars d1, through the intermediary of which selected knives are moved into cutting position, are mounted on the roll it instead of being included in the knife assembly itself, fewer slide bars are required in'my device. This is an economy in both weight and expense. It also enables longer or shorter knife assemblies to be used with the same knife-operating roll assembly if desired.

Various modifications and minor changes could be made in my machine Without departing from th'e prin ciple of the invention. While Ihave shown the preferred form in which my invention is carried out, it is not my intention to limit the same otherwise than is set forth in the claims.

I claim:

1. In a clipper machine of the character described, an anvil roll, feeding means for continuously moving sheet material over said anvil roll, a knife-operating roll located above said anvil roll and having its axis positioned in the same vertical plane with the anvil roll axis, an endless knife assembly including a pair of identical, laterally spaced, endless sprocket chains carrying knife-supporting elements and transversely extending, longitudinally spaced knives, means for moving said knife assembly at the same speed as said sheet material feeding means, said knife assembly passing around said knife-opearting roll, sprockets at opposite ends of said knife-operating roll engaging said sprocket chains respectively, means in said knife assembly normally maintaining said knives in inoperative position, slide bars mounted in the periphery of said knife-operating roll extending parallel to its axis, the spacing between said slide bars on said roll periphery corresponding to the longitudinal spacing between said knives in said knife assembly, engaging elements on said slide bars so arranged as to render said knives operative when said slidebars are moved into actuating position and con tact said knives, means on said knife-operating roll normally holding said slide bars out of actuating position, an actuating rod secured to the end of each slide bar and extending through the adjacent sprocket: on said knifeoperating roll, rod-moving means for each rod on said knife-operating roll beyond said last mentioned sprocket for moving the corresponding slide bar temporarily into actuating position, electric control switch assemblies carried by said knife-operating roll and connected with said rod-moving means respectively, electric contact means for selectively energizing said control switch assemblies, an endless knife-settable sprocket chain moving in unison with said endless knife assembly, settable elements carried by said knife-settable chain and spaced apart longitudinally the same distance as said knives in said knife assembly, and a contact switch engageable by said settable elements when said settable elements are manually set in switchengaging position, said last mentioned contact switch being electrically connected with said electric contact means whereby the setting of said settable elements for engagement with said last mentioned contact switch will cause corresponding knives in said knife assembly to be rendered operative through the medium of said slide bars and their control assemblies on said knife-operating roll.

2. In a clipper machine of the character described, an anvil roll, a knife-operating roll located above said anvil roll and having its axis positioned in the same vertical plane with the anvil roll axis, driving means rotating said anvil and said knife-opera ing rolls in opposite direction at the same peripheral speeds, means for continuously moving sheet material over said anvil roll at the same speed as said peripheral speeds, an endless knife assembly including a pair of identical, laterally spaced, endless sprocket chains carrying knife-supporting elements and transversely extending, longitudinally spaced knives, said knife assembly passing around said knife-operating roll, sprockets at opposite ends of said knife-operating roll engaging said sprocket chains respectively, spring means in said knife assembly normally maintaining said knives in inoperative position, slide bars mounted in the periphery of said knife-operating roll extending parallel to its axis, the spacing between said slide bars on said roll periphery corresponding to the longitudinal spacing between said knives in said knife assembly, engaging elements on said slide bars so arranged as to render said knives operative when said slide bars are moved into actuating position and contact said knives, means on said knife-operating roll normally holding said slide bars out of actuating position, an actuating rod secured to the end of each slide bar and extending through the adjacent sprocket on said knife-operating roll, rod-moving means for each rod on said knife-operating roll beyond said last mentioned sprocket for moving the corresponding slide bar temporarily into actuating position, electric control switch assemblies carried by said knife-operating roll and connected with said rod-moving means respectively, electric contact means for selectively energizing said control switch assemblies, an endless knife-settable sprocket chain moving in unison with said endless knife assembly, settable push buttons carried by said knife-settable chain and spaced apart longitudinally the same distance as said knives in said knife assembly, and a contact switch engageable by said push buttons when said push buttons are manually set in switch-engaging position, said last men tioned contact switch being electrically connected with said electric contact means, whereby the setting of said push buttons for engagement with said last mentioned contact switch will cause corresponding knives in said knife assembly to be rendered operative through the medium of said slide bars and their control assemblies on said knifeoperating roll.

3. In a clipper machine of the character described, an anvil roll, a knife-operating roll located above said anvil roll and having its axis positioned in the same vertical plane with the anvil roll axis, driving means rotating said anvil and said knife-operating rolls in opposite direction at the same peripheral speeds, means for continuously moving sheet material over said anvil roll at the same speed as said peripheral speeds, an endless knife assembly including a pair of identical, laterally spaced, endless sprocket chains carrying knife-supporting elements and transversely extending, longitudinally spaced knives, said knife assembly passing around said knife-operating roll, sprockets at opposite ends of said knife-operating roll engaging said sprocket chains respectively, spring means in said knife assembly normally maintaining said knives in inoperative position, slide bars mounted in the periphery of said knife-operating roll extending parallel to its axis, the spacing between said slide bars on said roll periphery corresponding to the longitudinal spacing between said knives in said knife assembly, cooperating elements on said slide bars and on said knife-supporting elements so arranged as to render said knives operative when said slide bars are moved into actuating position and contact said knives, means on said knife-operating roll normally holding said slide bars out of actuating position, an actuating rod secured to the end of each slide bar and extending through the adjacent sprocket on said knife-operating roll, rod-moving means for each rod on said knife-operating roll beyond said last mentioned sprocket for moving the corresponding slide bar temporarily into actuating position, electric control switch assemblies carried by said knife-operating roll and connected with said rodmoving means respectively, a stationary ring, contact members on said ring, each of said switch assemblies including contact elements engaging said contact members of said stationary ring upon the rotation of said knifeoperating roll, an endless knife-settable sprocket chain moving in unison with said endless knife assembly, settable push buttons carried by said knife-settable chain and spaced apart longitudinally the same distance as said knives in said knife assembly, and a contact switch engageable by said push buttons when said push buttons are manually set in switch-engaging position, said last mentioned contact switch being electrically connected with said contact members on said stationary ring, whereby the setting of said push buttons for engagement with said last mentioned contact switch will cause corresponding knives in said knife assembly to be rendered operative through the medium of said slide bars and their control assemblies on said knife operating roll.

4. in a clipper machine of the character described, an anvil roll, a knife-operating roll located above said anvil roll and having its axis positioned in the same vertical plane with the anvil roll axis, driving means rotating said anvil and said knife-operating rolls in opposite direction at the same peripheral speeds, means for continuously moving sheet material over said anvil roll at the same speed as said peripheral speeds, an endless knife assembly including a pair of identical, laterally spaced, endless sprocket chains carrying knife-supporting elements and transversely extending, longitudinally spaced knives, said knife assembly passing around said knife-operating roll, sprockets at opposite ends of said knife-operating roll engaging said sprocket chains respectively, spring means in said knife assembly normally maintaining said knives in inoperative position, slide bars mounted in the periphery of said knife-operating roll extending parallel to its axis, the spacing between said slide bars on said roll periphery corresponding to the longitudinal spacing between said knives in said knife assembly, cooperating elements on said slide bars and on said knife-supporting elements so arranged as to render said knives operative when said slide bars are moved into actuating position and contact said knives, spring means on said knife-operating roll normally holding said slide bars out of actuating position, an actuating rod secured to the end of each slid-e bar and extending through the adjacent sprocket on said knifeoperating roll, an air piston on the end of each rod and an air cylinder for each piston on said knife-operating roll beyond said last mentioned sprocket for moving the corre spending slide bar temporarily into actuating position, electric control switch assemblies carried by said knifeoperating roll and connected with said 'air cylinders respectively, a stationary ring, contact members on said ring, each of said switch assemblies including contact elements engaging said contact members of said stationary ring upon the rotation of said knife-operating roll, an endless knife-settable sprocket chain moving in unison with said endless knife assembly, said knife-settable chain passing around a sprocket wheel attached to said anvil roll, settable push buttons carried by said knife-settable chain and spaced apart longitudinally the same distance as said knives in said knife assembly, and a contact switch engageable by said push buttons when said push buttons are manually set in switch-engaging position, the contact of said knife-settable chain with said last mentioned sprocket wheel causing said push but-tons to be placed out of switch-engaging position, said last mentioned contact switch being electrically connected with said contact members on said stationary ring, whereby the setting of said push buttons for engagement with said last mentioned contact switch will cause corresponding knives in said knife assembly to be rendered operative through the medium of said slide bars and their control assemblies on said knife operating roll.

5. In a clipper machine of the character described, an anvil roll, a knife-operating roll located above said anvil roll and having its axis positioned in the same vertical plane with the anvil roll axis, driving means rotating said anvil and said knife-operating rolls in opposite direction at the same peripheral speeds, means for continuously moving sheet material over said anvil roll at the same speed as said peripheral speeds, the diameter of said anvil roll being greater than that of said knife-operating roll to provide greater distribution on the anvil roll periphery of the knife contacts with the anvil roll, an endless knife assembly including a pair of identical, laterally spaced, endless sprocket chains carrying knife-supporting elements and transversely extending, longitudinally spaced knives, said knife assembly passing around said knifeoperating roll, sprockets at opposite ends of said knifeoperating roll engaging said sprocket chains respectively, spring means in said knife assembly normally maintaining said knives in inoperative position, slide bars mounted in the periphery of said knife-operating roll extending parallel to its axis, the spacing between said slide bars on said roll periphery corresponding to the longitudinal spacing between said knives in said knife assembly, cooperating elements on said slide bars and on said knife-supporting elements so arranged as to render said knives operative when said slide bars are moved into actuating position and contact said knives, spring means on said knife-operating roll normally holding said slide bars out of actuating position, an actuating rod secured to the end of each slide bar and extending through the adjacent sprocket on said knifeoperating roll, an air piston on the end of each rod and an air cylinder for each piston on said knife-operating roll beyond said last mentioned sprocket for moving the corresponding slide bar temporarily into actuating position, electric control switch assemblies carried by said knife-operating roll and connected with said air cylinders respectively, a stationary ring, contact members on said ring, each of said switch assemblies including contact brushes engaging said contact members of said stationary ring upon the rotation of said knife-operating roll, an endless knife-settable sprocket chain moving in unison with said endless knife assembly, said knife-settable chain passing around a sprocket wheel attached to said anvil roll, settable push buttons carried by said knife-settable chain and spaced apart longitudinally the same distance as said knives in said knife assembly, and a contact switch engageable by said push buttons when said push buttons are manually set in switch-engaging position, the contact of said knife-settable chain with said last mentioned sprocket wheel causing said push buttons to be placed out of switch-engaging position, said last mentioned contact switch being electrically connected with said contact members on said stationary ring, whereby the setting of said push buttons for engagement with said last mentioned contact switch will cause corresponding knives in said knife assembly to be rendered operative through the medium of said slide bars and their control assemblies on said knife operating roll.

References Cited in the file of this: patent UNITED STATES PATENTS 465,427 Cox Dec. 15, 1891 1,703,962 Scholl Mar. 5, 1929 1,753,967 Robinson Apr. 8, 1930 1,781,900 Friede et'al Nov. 18, 1930 1,965,523 MacFarren July 3, 1934 2,005,824 Haumann June 25, 1935 2,369,253 Robinson et 'al Feb. 13, 1945 2,666,484 Schubert Jan. 19, 1954 

